Semiconductor devices are used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic equipment. Semiconductor devices are typically fabricated by sequentially depositing insulating or dielectric layers, conductive layers, and semiconductive layers of material over a semiconductor substrate, and patterning the various material layers using lithography to form circuit components and elements thereon. Many integrated circuits are typically manufactured on a single semiconductor wafer, and individual dies on the wafer are singulated by sawing between the integrated circuits along a scribe line. The individual dies are typically packaged separately, in multi-chip modules, for example, or in other types of packaging.
Semiconductor manufacturing technologies include a number of processes which involve complex physical and chemical interactions. The photolithography process is the process of transferring patterns of geometric shapes on a mask to a thin layer of photosensitive material (resist) covering the surface of a semiconductor wafer. The photolithography process is becoming a more sensitive and critical step in IC fabrication process as feature sizes shrink to ever-smaller sizes. However, there are many challenges related to the photolithography process.
Although existing photolithography process and methods of fabricating semiconductor device structure have generally been adequate for their intended purpose, they have not been entirely satisfactory in all respects.